The human body is comprised of many different solid organs (such as the liver or spleen) and luminal systems (such as the gastrointestinal tract or the urinary tract.) In many cases, it may be desirable or necessary to examine, diagnose, and/or treat disease processes that are located within, or on the side wall of a body lumen or cavity. A colonoscopy procedure is an example of how one might examine a luminal structure.
The human body is comprised of many different solid organs (such as the liver or spleen) and luminal systems (such as the gastrointestinal tract or the urinary tract.) In many cases, it may be desirable or necessary to examine, diagnose, and/or treat disease processes that are located within, or on the side wall of, a body lumen or cavity. A colonoscopy procedure is an example of how one might examine a luminal structure.
Colonoscopy involves the use of a flexible inspection device which is inserted into the distal end of the colon (rectum) and is advanced to the start of the colon (cecum.) Once the cecum is reached, the scope is withdrawn in order to examine the terminal ileum, colon, and rectum. Inspection of the colon and therapeutic maneuvers are primarily performed during the when the scope is being withdrawn. In addition to polyps (and tumors if present), the presence of erythema, erosions, ulcers, diverticula, melanosis coli, hemorrhoids, and condyloma are noted. A variety of diagnostic and therapeutic maneuvers can be performed during colonoscopy. These include endoscopic hemostasis, dilation of colonic or anastomotic strictures, stent placement for malignant disease, endoscopic mucosal resection of gastrointestinal tumors, foreign body removal, placement of colonic decompression tube, percutaneous endoscopic cecostomy tube placement, and tissue sampling and removal of visible lesions (also known as polyps). Sampling and removal of polyps is the most common maneuver performed during the procedure.
Colonoscopy has become the gold-standard screening and prevention tool for colorectal cancer as a result of the fact that precancerous polyps (known as adenomas) can be identified and removed during the procedure. For example, adenomas may be detected when they are identified by physicians visually inspecting the interior lining of the colon during the withdrawal phase of the procedure. As a result, methods and devices for enhancing adenoma detection generally aim to improve visualization of the colon and colonic mucosa. In addition to patients successfully completing pre-procedure bowel preparation and physicians investing sufficient time and attention performing withdrawal, optimal visualization can be ensured by obtaining sufficient insufflation/distention of the lumen, visualizing the entire circumference of the colon, inspecting behind and in between colonic folds, repeatedly inspecting areas (especially around turns) by back and forth movement of scope, and by reducing colonic contractions during withdrawal. New technologies aiming to enhance adenoma detection include high definition endoscopes with visual image enhancement, endoscopes that permit a wider field of vision, and accessory devices that attach to the tip of the scope and permit visualization behind mucosal folds. New methods for improving adenoma detection recently described in the literature include training staff to look for adenomas (on the screen/monitor) alongside the physician, the use of water (in addition to or in place of air or CO2) to clean and distend the colon, and the use of antispasmodic medication to reduce colon spasms.
Numerous studies have found a significant relationship between improved detection of adenomas during colonoscopy and reductions in the incidence of colorectal cancer among patients having undergone the procedure. For example, in an examination of 314,872 colonoscopies performed by 136 gastroenterologists over a ten year period Corley et al found that each 1% increase in Adenoma Detection Rate (ADR) resulted in a 3% reduction in the incidence of colorectal cancer.1 Accordingly, there is considerable need and demand for new technologies and methods that improve adenoma detection. 1 Corley, et al. Adenoma Detection Rate and Risk of Colorectal Cancer and Death. New England Journal of Medicine. 2014; 370: 1298-1306.